Ophthalmoscope.



PATENTED APR. 11, 1905.

H. L. DE ZENG.

OPHTHALMOSGOPE.

APPLIOATION FILED JULY 20,1904.

UNiTEo STATES Patented April 11, 1905.

ATENT UFFICE.

OPHTHALIVIOSCOPE.

SPECIFICATION forming part of Letters Patent No. 787,083, dated April 11, 1905.

Application filed July 20, 1904 Serial No. 217,361.

be it known that l, Hsxnv L. Di: Znxo, a citizen of the United States, residing in the city and county of Philadelphia, State of Pennsylvania, have invented a new and useful Improvement in Ophtlialmoscopi's, of which the following is a specification.

My invention consists of an ophthalmoscope adapted to permit the interior of an eye to be viewed without looking through a perforation in a reflector which is employed to direct light into the eye.

lt further consists of the employment of a test object or screen intermediate of a light source and the reflector of the ophthalmoscope, whereby the light fromsaid source and test object may be directed into the eye and shown upon the tissues thereof.

lt also consists of other details, as will be hereinafter described.

Figure 1 represents a side elevation of an ophthalmoscope embodying my invention. Fig. 2 represents a partial longitudinal section and partial side elevation opposite to that shown in Fig. I. Fig. 3 represents a partial longitudinal section on line are, Fig. 1, and front view of the adjacent portion of the ophthalmoscope. Fig. -t represents a side elevation of a detached portion. Fig. 5 represents a transverse section on line Fig. 3. Fig. 6 represents a section on line .2, Fig. 3. Fig. 7 shows a modification of the illuminator.

Similar letters of reference indicate corresponding parts in the figures.

lteferring to the drawings, A designates an ophthalmoscope which, excepting theifoatures of my invention applied thereto, is of usual construction.

designates the tubular handle of the instrument, within which is an illuminator C, which in the present case is of the form of an electric light.

l) designates a reflector of the instrument, the same being locatedbelow the viewing aperture E and occupying an inclined position over the condensing-lens F in the adjacent end of the handle B.

Within the handle B is the test object or screen it, consisting of a glass disk having on the face thereof a series of radiating lines H,

said disk being mounted on a sleeve .1, which is movable within the handle, and having attached to it the lingerpiece K, which is convenient of access on the exterior of the handle.

In the wall of the tube is a longitudinallyextending slot L, on whose walls are the scales or grzuluations M, it being noticed that a relative mark M on the sleeve J is visible through said slot, it being evident that as the test object is movableand accordingly adjustable the extent ofadjustment may be recorded, it being also noticed that the test object and the condensing-lens are interposed between the source of light and the reflector, and thus the test object may be focused within the eye, and that the interior of the eye may be viewed without looking through the reflector, as the latter is without a peep-opening, it being imperforate and intact.

in Fig. 7 I show a modification where an auxiliary lens 1 is located in the handle between the test object and the light sou rcc or illuminator, thus increasing the reflex in the pupilary area.

lt will be seen from the foregoing description that the adaptation of the test object to an ophthalmoscope enables the user to determine the exact character and amount of the ocular refraction, as the relative position of the said test object and the condensing-lens will cause the rays of light from the test object to be projected into the eye in either a parallel, convergent, or divergent direction, as recorded upon the graduated scale. It will also enable the observer to detect and measure the astigmatism when present, as no one position of the test object will render all of the radiating lines equally distinct upon the retina of the eye under examination, and the dilference in the two positions at which the right-angle lines of the test object are most distinct is a measure of the astigmatism.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In an ophthalmoscope, the combination of a source of light, a test object and a reflector for directing the light from the said test object into the eye, means for focusing the light from' the said test object upon the retina of the eye and means exterior to the said refiector for viewing the retina, substantially as shown and described.

2. In an ophthalmoscope, the combination of a source of light, a test object and a reflector for directing the light from the said test object into the eye, means for focusing the light from the said test object upon the retina of the eye and means located to the rear of and exterior to the said reflector for viewing the retina, substantially as shown and described.

3. In an ophthallnoscope. the combination of a source of light, a test object and a reflecof a source of light, a test object and a reflector for directing the light from the said test object into the eye, means for focusing the light from the said test object upon the retina of the eye and means located above and to the rear of the edge of the reflector for viewing the retina, substantially as shown and described.

5. In an ophthalmoscope, the combination of a source of light, a test object and a reflector for'directing the light from the said test object into the eye, means for focusing the light from the said test object upon the retina of the eye, and means adjacent and exterior to the outer edge of the reflector for viewing the retina, substantially as shown and described.

HENRY L. DE ZENG.

Witnesses:

JOHN A. VVIEDERsHEIM, WM. CANER WIEDERSEIM. 

